Hello everyone,
Long story short, somehow I managed to broke keyboard backlight in my good old T430. Stupid me
I probably shorted something and backlight seemed to stopped working entirely. Right now when I tap Fn+Space the backlight comes on, but it's so dim, it's barely visible. If you watch the keyboard at certain angle, you can see the light coming from under the keys but if you turn off the light, it's like the backlight is non-existent.
Level 1 and level 2 backlight give the same amount of light (close to none). I have downloaded the schematics from here (whichever god, bless this forum, seriously):
https://www.badcaps.net/forum/showpo...97&postcount=4
and looking at page 63, I thought that maybe R13 is the culprit, but then other LEDs should have the same problem, right? (of course they don't). Still, checked it, it's around 218 Ohms, so I'm clearly looking in the wrong place.
I have checked what's happening with the voltage on the speaker mute line and clearly there's a drop when you press the button and LED turns on. I guess it would be too simple if keyboard backlight was just driven by voltage, so there are 2 things left:
-kbd_bl_dtct (I'm guessing that's "detect", so tapping Fn+Space actually turns on the backlight instead of just the "lamp" near the camera)
-kbd_bl_pwm - and I'm afraid that's the culprit here - LEDs are not driven properly, therefore they're barely lit, trying to increase the brightness does nothing, looks reasonable
...and that's the part where I hit a wall, because I wasn't born as "electronics guy" and I wonder if R8826 died or MEC1619 GPIO153 is broken*.
That's at least how I thought it might be, please correct me if any of my assumptions are wrong. I'd be quite happy if it could be fixed easily, as replacing the motherboard (which would be cheaper than replacing that chip) is a last resort for me (mainly because I have heavily modded BIOS, replaced WLAN, etc. and that would stop working if I replaced the mobo).
*I didn't disassembly the thing - I'm writing this post on it to be honest, as I see no point in ripping it apart if you guys say "don't bother the resistor, EC is kill" - after all it's not a major problem making the machine unusable, just a nuisance.
Long story short, somehow I managed to broke keyboard backlight in my good old T430. Stupid me
I probably shorted something and backlight seemed to stopped working entirely. Right now when I tap Fn+Space the backlight comes on, but it's so dim, it's barely visible. If you watch the keyboard at certain angle, you can see the light coming from under the keys but if you turn off the light, it's like the backlight is non-existent.
Level 1 and level 2 backlight give the same amount of light (close to none). I have downloaded the schematics from here (whichever god, bless this forum, seriously):
https://www.badcaps.net/forum/showpo...97&postcount=4
and looking at page 63, I thought that maybe R13 is the culprit, but then other LEDs should have the same problem, right? (of course they don't). Still, checked it, it's around 218 Ohms, so I'm clearly looking in the wrong place.
I have checked what's happening with the voltage on the speaker mute line and clearly there's a drop when you press the button and LED turns on. I guess it would be too simple if keyboard backlight was just driven by voltage, so there are 2 things left:
-kbd_bl_dtct (I'm guessing that's "detect", so tapping Fn+Space actually turns on the backlight instead of just the "lamp" near the camera)
-kbd_bl_pwm - and I'm afraid that's the culprit here - LEDs are not driven properly, therefore they're barely lit, trying to increase the brightness does nothing, looks reasonable
...and that's the part where I hit a wall, because I wasn't born as "electronics guy" and I wonder if R8826 died or MEC1619 GPIO153 is broken*.
That's at least how I thought it might be, please correct me if any of my assumptions are wrong. I'd be quite happy if it could be fixed easily, as replacing the motherboard (which would be cheaper than replacing that chip) is a last resort for me (mainly because I have heavily modded BIOS, replaced WLAN, etc. and that would stop working if I replaced the mobo).
*I didn't disassembly the thing - I'm writing this post on it to be honest, as I see no point in ripping it apart if you guys say "don't bother the resistor, EC is kill" - after all it's not a major problem making the machine unusable, just a nuisance.
